Eliminate outgoing InterfaceProvider

services/shell/tests/connect/connect_test_app_manifest.json

 {
   "manifest_version": 1,
   "name": "mojo:connect_test_app",
   "display_name": "Connect Test App",
   "capabilities": {
     "required": {
+      "mojo:connect_unittests": {
+        "interfaces":  [ "shell::test::mojom::ExposedInterface" ]
+      },
       "mojo:connect_test_a": {
         "interfaces": [ "shell::test::mojom::ConnectTestService" ]
       },
       "mojo:connect_test_class_app": {
         "classes": [ "class" ],
-        "interfaces": ["shell::test::mojom::ConnectTestService"]
+        "interfaces": [ "shell::test::mojom::ConnectTestService" ]
       },
       "mojo:shell": { "classes": [ "shell:user_id" ] }
     }
   }
 }